Inverter-based generator and welding system

ABSTRACT

A system includes an engine configured to drive a generator to produce a first power output, and a first inverter communicatively coupled to the generator. The first inverter is configured to convert the first power output into a second power output. The system includes a second inverter communicatively coupled to the generator. The second inverter is configured to convert the first power output into a third power output. The third power output includes a welding power output.

BACKGROUND

The invention relates generally to welding systems and, moreparticularly, to inverter-based welding systems.

Welding is a process that has become increasingly ubiquitous in variousindustries and applications. As such, a variety of welding applications,such as construction and shipbuilding, may require welding devices thatare portable and can easily be transported to a remote welding location.Accordingly, in some cases, it is often desirable for such weldingdevices to be operable as standalone units remote from a power grid orother primary power source. Therefore, a variety of welding systemsutilizing alternate power sources, such as small gasoline-fueledengines, have been developed. However, certain welding tasks such aswelding performed off-road or remotely to quickly repair certainequipment and/or other machinery, for example, may include load demandsthat are very small as compared to other larger welding tasks. It may beuseful to provide a more compact and efficient portable welding system.

BRIEF DESCRIPTION

In one embodiment, a system includes an engine configured to drive agenerator to produce a first power output, and a first invertercommunicatively coupled to the generator. The first inverter isconfigured to convert the first power output into a second power output.The system includes a second inverter communicatively coupled to thegenerator. The second inverter is configured to convert the first poweroutput into a third power output. The third power output includes awelding power output.

In a second embodiment, a welding power supply unit includes an engineconfigured to drive a generator to produce a first power output, and afirst inverter communicatively coupled to the generator. The firstinverter is configured to convert the first power output into a secondpower output. The welding power supply unit includes a second invertercommunicatively coupled to the generator. The second inverter isconfigured to convert the first power output into a welding poweroutput. The welding power supply unit includes a welding torchdetachably coupled to the welding power supply unit and configured toreceive the welding power output.

In a third embodiment, a welding system includes an enclosure. Theenclosure includes an engine configured to drive a generator to producea first power output, and a plurality of inverters communicativelycoupled to the generator. The plurality of inverters is configured toconvert the first power output into a second power output and a thirdpower output concurrently. The third power output includes a weldingpower output.

DRAWINGS

These and other features, aspects, and advantages of the presentinvention will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike characters represent like parts throughout the drawings, wherein:

FIG. 1 is a perspective view of an inverter-based power supply unit,which functions to power, control, and provide consumables to a weldingoperation and/or auxiliary equipment;

FIG. 2 is a schematic diagram of the inverter-based power supply unit ofFIG. 1 including a welding circuit, in accordance with presentembodiments; and

FIG. 3 is a series of plots illustrating the power conversion techniquesand outputs of the inverter-based power supply unit of FIG. 1, inaccordance with present embodiments.

DETAILED DESCRIPTION

Present embodiments relate to an inverter-based generator and weldingsystem. In certain embodiments, the inverter-based generator and weldingsystem may be useful in permitting the system to be moved from place toplace relatively easily, or may be designed as a generally stationarysystem. Moreover, the inverter-based generator and welding system may bedesigned for field operation, in which case it may include anengine-generator unit within the enclosure that provides the necessarypower for a given welding operation. Thus, the inverter-based generatorand welding system may be designed for use in various applications andlocations (e.g., remote locations, locations away from typical workareas or workstations, off-road locations, and so forth) in which one ormore sources of utility power may be at least temporarily inaccessible.Furthermore, in certain embodiments, the inverter-based generator andwelding system may be configured to operate as a standalone generator, astandalone welder, or concurrently as a standalone generator and as astandalone welder. In this manner, the inverter-based generator andwelding system may provide an operator with the advantage of havingsufficient power for auxiliary equipment (e.g., lighting at a campsiteor other off-road worksite) as well as sufficient power to perform oneor more welding operations (e.g., at the campsite or the off-roadworksite).

With the foregoing in mind, an embodiment of a generator and weldingsystem, such as an inverter-based generator and welding system 10, isillustrated in FIG. 1. The inverter-based welding system 10 may providepower and control for a welding operation and/or auxiliary equipment.The inverter-based welding system 10 may include a power supply unit 12enclosed in a cabinet or enclosure 14. As previously noted, in certainembodiments, the inverter-based welding system 10 may be useful inenabling the power supply unit 12 to be moved from place to placerelatively easily, or may be designed as a generally stationary system.Moreover, the inverter-based welding system 10 may be designed for fieldoperation, in which case it may include, for example, one or more of anengine-generator unit, a fuel cell, and an energy storage device withinthe enclosure 14 that provide the necessary power for a given weldingoperation or other application. In certain embodiments, theinverter-based welding system 10 may be designed for use in variouslocations (e.g., remote locations, locations away from typical workareas or workstations, off-road locations, and so forth) in which one ormore sources of utility power may be at least temporarily inaccessible.Thus, the power supply unit 12 may operate as a standalone unit,generating the power necessary for a welding operation and/or auxiliaryoperations while isolated from additional power sources.

As further illustrated by FIG. 1, the power supply unit 12 may include acontrol panel 16, through which an operator may, for example, controlthe machine operational characteristics, such as power, weld output, andso forth, for a welding operation via dials and switches 18. The controlpanel 16 may also include an auxiliary power output receptacle 20 andwelding power output connectors 21 for outputting alternating current(AC) and/or direct current (DC) output power, respectively. As theoperator adjusts operating parameters via the control panel 16, signalsmay be generated and received by one or more control circuits that maybe included within the power supply unit 12. The power supply unit 12controller may implement the desired welding operation in accordancewith these inputs. For example, in one embodiment, the controller mayimplement a constant current regime for use with a shielded metal arcwelding (SMAW) or stick welding operation and/or process type.

In certain embodiments, an electrode assembly 22 may extend from thewelding power output connectors 21 of the power supply unit 12 to thelocation of the weld. A first cable 24 and a welding torch 26 may becoupled to the power supply unit 12 as components of the electrodeassembly 22. The welding torch 26 may be used to secure a weldingelectrode suitable for shielded metal arc welding (SMAW) (e.g., stickwelding) operations. A work assembly 28 extending from the welding poweroutput connectors 21 of the power supply unit 12 to the weld includes asecond cable 30 terminating in a work lead clamp 32. During, forexample, a weld operation, the work lead clamp 32 may be coupled to aworkpiece 34 to create a circuit between the welding torch 26, theworkpiece 34, and the power supply unit 12. That is, as the weldingoperator, for example, contacts or closely approaches the tip of theelectrode of the welding torch 26 to the workpiece 34, an electricalcircuit is completed through the cables 24 and 30, the welding torch 26,the workpiece 34, and the work lead clamp 32 to generate an electricalarc between the electrode tip and the workpiece 34 to perform a weld ofthe workpiece 34.

In certain embodiments, as further illustrated by FIG. 1, a detachable(e.g., removable) receptacle 36 may be included as part of the powersupply unit 12. The detachable receptacle 36 may be useful in storingone or more components of the inverter-based welding system 10. Forexample, the detachable receptacle 36 may be a pouch, a tote, or similarreceptacle that may couple to an exterior portion of the power supplyunit 12. As the inverter-based welding system 10 may be used as aportable (e.g., capable of being hand-carried by a single operator ortransported from place to place by a single operator) generator and/orwelding generator, the detachable receptacle 36 may be provided tofacilitate the portability of the inverter-based welding system 10. Forexample, the detachable receptacle 36 may be used by an operator of theinverter-based welding system 10 to package or store one or morecomponents (e.g., the cable 24, the welding torch 26, and so forth) ofthe electrode assembly 22 and/or components (e.g., the cable 30, thework lead clamp 32, and so forth) of the work assembly 28.

FIG. 2 illustrates a schematic embodiment of the inverter-based powersupply unit 12 of FIG. 1. As illustrated, the inverter-based powersupply unit 12 may include an engine 38, a generator 40, a DC bus 42,inverters 43 and 44, a step-down and/or isolation transformer 46, outputcircuits 47 and 48, and control circuitry 50 all enclosed within thesingle enclosure 14. In certain embodiments, the inverter-based powersupply unit 12 may be used to generate commanded power output levels foran auxiliary operation and/or welding operation, as described in detailbelow. Such commanded power output levels may be commanded based on oneor more of amperage, voltage, wire type, wire feed speed, electrodediameter, and so forth. As such, the engine 38 may be used to drive thegenerator 40 to produce power (e.g., electrical power), which may beutilized to provide an auxiliary power output 52 (e.g., AC electricaloutput), to power an additional device or other auxiliary equipment(e.g., lights, grinding equipment, cutting tools, and so forth) and/orto produce a welding power output 54 (e.g., DC electrical output).

The engine 38 may include a fuel source useful in providing power to thegenerator 40. The engine 38 may include a combustion engine powered bygasoline, diesel, LP fuel, natural gas, or other fuels, and may beconfigured to drive one or more rotating drive shafts. For example, inone embodiment, the engine 38 may include an industrial gas/dieselengine having a power rating of below approximately 15 hp, belowapproximately 10 hp, or below approximately 5 hp. Thus, at theaforementioned power ratings and physical size, the engine 38 may bereferred to as a small industrial engine. The generator 40 coupled tothe engine 38 may convert the power output (e.g., mechanical energy) ofthe engine 38 into electrical power, producing an alternating current(AC) voltage output. In certain embodiments, the generator 40 may berated at less than approximately 1000 watts (W), less than approximately2000 W, less than approximately 3000 W, less than approximately 4000 W,or otherwise up to approximately 5000 W.

As previously noted, the power supply unit 12 may include the DC bus 42and the inverters 43 and 44. The DC bus 42 may include a bridgerectifier 56 connected to a bus capacitance 58 (Cbus). In certainembodiments, the bridge rectifier 56 may include a configuration (e.g.,an H-bridge configuration) of diodes (e.g., D1, D2, D3, and D4) forconverting (e.g., rectifying) the incoming AC voltage signal (e.g.,115V, 120V, 200V, 208V, 230V, or similar voltage rating) generated viathe generator 40 into a filtered direct current (DC) voltage signal. Ifa low AC voltage is supplied by the generator 40, a boost circuit couldbe incorporated into the DC bus 42 to raise the voltage to the desiredoperational level. The rectified and filtered DC voltage signal may thenbe transmitted to power switches 60 (e.g., semiconductor switches Q1,Q2, Q3, Q4) of the auxiliary inverter 43 or to power switches 62 (e.g.,semiconductor switches Q5, Q6, Q7, Q8) of the welding power inverter 44to respectively produce the AC auxiliary power output 52 and the DCwelding power output 54.

Specifically, the power switches 60 (e.g., switches Q1, Q2, Q3, Q4) mayconvert the rectified and filtered DC voltage signal into an AC voltagesignal, which may be then filtered via an inductor 64 and capacitor 66of the output circuit 47 to produce a constant AC auxiliary power output52. It should be appreciated that the power switches 60 and 62 mayinclude any configuration of integrated power electronic switchingdevices such as insulated gate bipolar transistors (IGBTs), field-effecttransistors (FETs), and so forth, which may be controlled (e.g., by thecontrol circuitry 50) to switch from “ON” (e.g., activated) and “OFF”(e.g., deactivated) states to control the power conversion via theinverter 43 and/or inverter 44, and by extension, the AC auxiliary poweroutput 52 and the DC welding power output 54.

For example, in a similar manner, the power switches 62 (e.g., switchesQ5, Q6, Q7, Q8) may convert the rectified and filtered DC voltage signalinto an AC voltage signal, which may be then reduced (e.g., steppeddown) via a step-down and/or isolation transformer 46 to a voltage level(e.g., approximately 70 VAC, or other similar voltage rating) suitablefor producing a welding power output. The transformer 46 may be anydevice capable of reducing the AC voltage signal produced, for example,by the power switches 62 of the inverter 44 to a voltage level suitablefor producing a welding power output to supply to the welding torch 26.The transformer 46 may also be used to isolate the welding-specificcircuitry of the inverter-based power supply unit 12 from the ACauxiliary power output 52 circuitry of the power supply unit 12. Theoutput circuit 48 may then convert the welding-level AC voltage signalreceived from the transformer 46 back into a DC voltage signal via anoutput rectifier 68. The new DC voltage signal may be then useful forsupporting various welding operations and/or processes (e.g., a SMAWwelding process).

Although not illustrated, as previously noted, it should be appreciatedthat the AC auxiliary power output 52 may be used to power anotherexternal device and/or other auxiliary equipment. For example, theinverter-based power supply unit 12 may supply the voltage AC auxiliarypower output 52 to external lighting equipment, grinding equipment,cutting tools, and so forth. Likewise, as noted above, theinverter-based power supply unit 12 may also be used to generate awelding power output, for example, to perform one or more weldingoperations. Furthermore, by providing the inverters 43 and 44 inconjunction with the engine 38 and generator 40, the inverter-basedpower supply unit 12 may operate markedly quieter than other generatorand/or welding systems.

In certain embodiments, as further illustrated by FIG. 2, the engine 38,the generator 40, the DC bus 42, and the inverters 43 and 44 may each becontrolled and/or commanded by the control circuitry 50. The controlcircuitry 50 may include an analog control circuit, or it may include aprocessor 70 and/or other data processing circuitry that may becommunicatively coupled to a memory 72 to execute instructions tocontrol, for example, one or more parameters of the engine 38, thegenerator 40, and the bridge rectifier 56, and the power switches 60 and62 of the respective inverters 43 and 44. These instructions may beencoded in programs or code stored in tangible non-transitorycomputer-readable medium, such as the memory 72 and/or other storage.The processor 70 may be a general purpose processor, system-on-chip(SoC) device, application-specific integrated circuit (ASIC), or otherprocessor configuration. Similarly, the memory 72 may include, forexample, random-access memory (RAM), read-only memory (ROM), flashmemory (e.g., NAND), and so forth.

In one embodiment, the control circuitry 50 may be useful in controllingthe power switches 60 and 62 of the respective inverters 43 and 44, orother components of the inverter-based power supply unit 12 to produce astabilized AC power output (e.g., AC auxiliary power output 52) to powerauxiliary equipment and/or a stabilized DC welding power output tosupport one or more welding operations and/or processes. For example,the inverter-based power supply unit 12 may be used to support a stick(SMAW) welding process, which may generally use a constant current (CC)welding power output controlled by the control circuitry 50. In such anembodiment, the control circuitry 50 may control the amperage output(e.g., amperage of an electrical arc generated via the welding torch 26)to a predetermined CC value by adjusting voltage and/or amperagefeedback signals detected at the output stage of the inverter 44. Inother embodiments, the inverter-based power supply unit 12 may be usedto perform other user-selected welding processes, such as a flux coredwelding process, a metal inert gas (MIG) welding process, and the like.

In certain embodiments, the welding power output 54 may be generated inplace of, in addition to, or concurrently (e.g., at the same time) withthe AC auxiliary power output 52. That is, the power supply unit 12 mayproduce the AC auxiliary power output 52 and the DC welding power output54 substantially simultaneously (e.g., occurring at substantially thesame time) and/or concurrently (e.g., occurring in parallel or atsubstantially the same time). For example, during operation, if thepower supply unit 12 is operating at an output power rating of, forexample, approximately 3000 W, the power supply unit 12 may provide 3000W of power as the AC auxiliary power output 52, 3000 W of power as theDC welding power output 54, or concurrently provide 1500 W for each ofthe AC auxiliary power output 52 and the DC welding power output 54 atsubstantially the same time.

Nevertheless, it should be appreciated that the power provided as therespective power outputs 52 and 54 may be dependent upon the specificauxiliary equipment receiving the power output 52 and/or the specificwelding operation or task being performed via the power output 54. Thus,when the power supply unit 12 supplies the power outputs 52 and 54concurrently, the total power output (e.g., 1000 W, 2000 W, 3000 W, 3500W, and so forth) may or may not be divided evenly between the respectivepower outputs 52 and 54. Furthermore, as the present embodiments of theinverter-based power supply unit 12 may be designed for use in variouslocations (e.g., remote locations, locations away from typical workareas or stations, off-road locations, and so forth), having the abilityto operate as a standalone generator, a standalone welder, orconcurrently as a standalone generator and as a standalone welder mayallow an operator the advantage of having sufficient power for auxiliaryequipment (e.g., lighting at a campsite or other off-road worksite) aswell as sufficient power to perform one or more welding operations(e.g., at the campsite or the off-road worksite).

FIG. 3 depicts a series of waveform plots 76, 78, 80, and 82illustrating examples of the previously discussed power conversion andcontrol techniques of the inverter-based power supply unit 12implemented using, for example, the control circuitry 30. As illustratedby plot 76 of FIG. 3, the control circuitry 50 may generate a referencesine wave AC voltage signal 86 (e.g., modulating signal) to be comparedagainst a generated triangular wave AC voltage signal 84 (e.g.,saw-tooth carrier signal). Similarly, the control circuitry 50 may alsocompare an inversion of the sine wave AC voltage signal 86 against thetriangular wave AC voltage signal 84. The AC voltage signal 86 may alsobe totally synthesized within software stored in the memory 72 of the inthe control circuitry 50. The signals 84 and 86 may then be used todrive and/or control the power switches 60 of the inverter 43 and/or thepower switches 62 of the inverter 44. The resultant output voltagesignal of the inverter 43 and/or the inverter 44 may be a pulse-widthmodulated (PWM) inverted signal 90 as illustrated by plot 78. To producethe auxiliary power output 52, the signal 90 may be then filtered (e.g.,filtered via the AC output circuit 47) to produce a filtered (e.g.,“clean” and stabilized) AC voltage signal as the auxiliary power output52, as illustrated by plot 80. As previously noted, the auxiliary poweroutput 52 may be provided at the power receptacle 20 of theinverter-based power supply unit 12 to which an external device and/orother auxiliary equipment (e.g., lighting equipment, grinding equipment,cutting tools, and so forth) may be coupled.

In a similar manner, to produce the welding power output 54, a volt ampsignal 91 of plot 82 may be reduced (e.g., stepped down) via thetransformer 46 and converted via the DC output circuit 48 to produce aDC welding voltage signal (e.g., CC welding output) as the welding poweroutput 54, as illustrated by plot 82. As also previously noted, thewelding power output 54 may be provided to the welding torch 26 of theinverter-based power supply unit 12, which may be then used to generatean electrical arc to perform one or welding operations and/or processes.It should again be appreciated that the inverter-based power supply unit12 may produce the auxiliary power output 52 and the welding poweroutput 54 individually or substantially simultaneously (e.g., inparallel).

While only certain features of the invention have been illustrated anddescribed herein, many modifications and changes will occur to thoseskilled in the art. It is, therefore, to be understood that the appendedclaims are intended to cover all such modifications and changes as fallwithin the true spirit of the invention.

The invention claimed is:
 1. A system, comprising: a portable,self-contained power supply unit configured to be hand-carried by asingle operator, wherein the portable, self-contained power supply unitcomprises: an engine configured to drive a generator to produce a firstpower output, wherein the engine comprises a power rating ofapproximately 10 horsepower (hp) or less; a direct current (DC) buscomprising a rectifier, wherein the DC bus is configured to provide DCpower from the first power output; a first inverter electrically coupledbetween the DC bus and auxiliary output circuitry, wherein the firstinverter is configured to convert the first power output into a secondpower output, wherein the second power output comprises an auxiliarypower output; and a second inverter electrically coupled between the DCbus and welding output circuitry, wherein the second inverter isconfigured to convert the first power output into a third power output,wherein the third power output comprises a welding power output.
 2. Thesystem of claim 1, wherein the generator comprises a power rating ofapproximately 3500 watts (W) or less.
 3. The system of claim 1, whereinthe first inverter and the second inverter each comprises a plurality ofpower switches configured to invert the first power output in parallel.4. The system of claim 3, comprising a welding torch, wherein thewelding power output comprises a direct current (DC) welding poweroutput delivered to the welding torch.
 5. The system of claim 1, whereinthe power supply unit is configured to produce the second power outputand the third power output substantially simultaneously.
 6. The systemof claim 1, wherein the first inverter is configured to provide thesecond power output to an auxiliary device coupled to the system,wherein the second power output comprises an alternating current (AC)auxiliary power output.
 7. The system of claim 1, comprising: atransformer coupled to the second inverter, wherein the transformer isconfigured to reduce the third power output; and a direct current (DC)output circuit coupled to the transformer, wherein the DC output circuitis configured to rectify the third power output to provide a DC outputas the welding power output.
 8. The system of claim 1, comprising awelding torch and a work lead clamp, wherein the welding torch isconfigured to receive the welding power output to generate a weldingarc.
 9. The system of claim 1, comprising control circuitry, wherein thecontrol circuitry is configured to adjust the welding power outputaccording to a user-selected welding process type.
 10. The system ofclaim 9, wherein the user-selected welding process type comprises ashielded metal arc welding (SMAW) process.
 11. A welding power supplyunit, comprising: a portable, self-contained welding power supply unitconfigured to be hand-carried by a single operator, wherein theportable, self-contained welding power supply unit comprises: an engineconfigured to drive a generator to produce a first power output, whereinthe engine comprises a power rating of approximately 10 horsepower (hp)or less and the generator comprises a power rating of approximately 3500watts (W) or less; a direct current (DC) bus comprising a rectifier,wherein the DC bus is configured to provide DC power from the firstpower output; a first inverter electrically coupled between the DC busand auxiliary output circuitry, wherein the first inverter is configuredto convert the first power output into an auxiliary power output; asecond inverter electrically coupled between the DC bus and weldingoutput circuitry, wherein the second inverter is configured to convertthe first power output into a welding power output; and a welding torchdetachably coupled to the welding power supply unit and configured toreceive the welding power output.
 12. The welding power supply unit ofclaim 11, wherein the first inverter is configured to provide theauxiliary power output to an auxiliary device coupled to the weldingpower supply unit, wherein the auxiliary power output comprises analternating current (AC) auxiliary power output.
 13. The welding powersupply unit of claim 11, wherein the welding power supply unit isconfigured to produce the auxiliary power output and the welding poweroutput substantially simultaneously.
 14. The welding power supply unitof claim 11, wherein the welding output circuitry comprises: atransformer coupled to the second inverter, wherein the transformer isconfigured to reduce a voltage of the welding power output; and a directcurrent (DC) output circuit coupled to the transformer, wherein the DCoutput circuit is configured to rectify the welding power output toprovide a direct current (DC) welding power output as the welding poweroutput to the welding torch.
 15. A welding system, comprising: anenclosure configured to be hand-carried by a single operator,comprising: an engine configured to drive a generator to produce a firstpower output, wherein the generator comprises a power rating ofapproximately 3500 watts (W) or less; a direct current (DC) buscomprising a rectifier, wherein the DC bus is configured to provide DCpower from the first power output; and a plurality of inverterselectrically coupled to the DC bus, wherein a first inverter of theplurality of inverters is coupled between the DC bus and auxiliaryoutput circuitry and a second inverter of the plurality of inverters iscoupled between the DC bus and welding output circuitry, wherein theplurality of inverters is configured to convert the first power outputinto a second power output and a third power output substantiallyconcurrently, and wherein the third power output comprises a weldingpower output.
 16. The welding system of claim 15, comprising areceptacle detachably coupled to the welding system, wherein thereceptacle comprises a pouch or a tote configured to detachably coupleto an external portion of the welding system.
 17. The welding system ofclaim 15, wherein the plurality of inverters is configured to convertthe first power output into an alternating current (AC) auxiliary poweroutput as the second power output, and to convert the first power outputinto a direct current (DC) power output as the welding power output. 18.The welding system of claim 15, comprising one or more componentsconfigured to detachably couple to the welding system to perform anoperation, wherein the one or more components comprises a welding cable,a welding torch, a work lead clamp, an auxiliary device, or anycombination thereof.